Chernobyl disaster: The City of Chernobyl is evacuated six days after the disaster.

On 26 April 1986, the no. 4 reactor of the Chernobyl Nuclear Power Plant, located near Pripyat, Ukrainian SSR, Soviet Union, exploded. With dozens of direct casualties, it is one of only two nuclear energy accidents rated at the maximum severity on the International Nuclear Event Scale, the other being the 2011 Fukushima nuclear accident. The response involved more than 500,000 personnel and cost an estimated 18 billion rubles. It remains the worst nuclear disaster and the most expensive disaster in history, with an estimated cost of US$700 billion.

Chernobyl, officially called Chornobyl, is a partially abandoned city in Vyshhorod Raion, Kyiv Oblast, Ukraine. It is located within the Chernobyl Exclusion Zone, 90 kilometres (60 mi) to the north of Kyiv and 160 kilometres (100 mi) to the southwest of Gomel in neighbouring Belarus. Prior to being evacuated in the aftermath of the Chernobyl disaster in 1986, it was home to approximately 14,000 residents—considerably less than adjacent Pripyat, which was completely abandoned following the incident. Since then, although living anywhere within the Chernobyl Exclusion Zone is technically illegal, Ukrainian authorities have tolerated those who have taken up living in some of the city's less irradiated areas; Chernobyl's 2020 population estimate was 150 people.